SpaceX has been forced to ground its Starship rocket while it conducts an investigation into an incident during its most recent test flight.The US Federal Aviation Administration (FAA) flagged an anomaly during the 22 May launch, which saw the world’s biggest rocket lift off from SpaceX’s Starbase facility in Texas before the second stage performed a controlled landing in the Indian Ocean.The first stage Super Heavy booster encountered an issue while splashing down in the Gulf of Mexico, with only one of its 33 engines lighting.This caused the 72 metre (236 foot) rocket to impact the water so heavily that the FAA classified it as a mishap, meaning there must now be an investigation before any further flights with the rocket.“After a thorough assessment of the operation, the FAA has determined the 22 May SpaceX Starship Flight 12 launch resulted in a mishap,” the regulator said in a statement.“A return to flight of the Starship Super Heavy vehicle is based on the FAA determining that any system, process, or procedure related to the mishap does not affect public safety.”When the first and second stage Starship rockets are fully stacked on the launch pad, they measure more than 124 metres.This makes it more than 10 metres taller than Nasa’s Saturn V rocket, which was used during the Apollo program to take astronauts to the Moon.SpaceX plans to use Starship to return humans to the lunar surface for the first time in more than 50 years as part of Nasa’s Artemis program, though delays to the rocket’s development have forced the US space agency to push back its timeline.The first crewed mission to the Moon are currently scheduled to take place in 2028, having originally been set to take place in 2024.A major reason for the delays has been the readiness of Starship and its lunar landing system, with SpaceX boss Elon Musk citing the “alien-level technology” involved in building the world’s biggest rocket.As part of the latest mishap investigation, any corrective actions will need to be approved by the FAA before another Starship launch takes place.